The present invention relates to an improvement in semiconductor laser apparatus which radiates invisible light. More particularly, the invention relates to infrared diode laser apparatus with a simplified adjustment of its optical axis.
Recently, an atmospheric gas monitor system and gas leak monitor system utilizing an infrared beam were widely placed in practical use. These systems utilize the principle of infrared absorption spectrometry. Basically, an optical path for measurement is set between an infrared light source and an infrared light detector, and contamination or source gas leakage is defined by the amount of absorption of infrared light. However, a system for monitoring the gas condition along a path having a length of several hundred meters on a real time basis utilizing a laser as the infrared light source and setting an indoor optical path for measurement has a considerable problem in how to adjust the emitting axis of the invisible infrared laser to the optical axis of the detector.
It is well known at the present time to superimpose the visible laser beam with the infrared laser beam upon adjusting the optical axis of the infrared laser source in a long-path infrared gas detection system. This optical axis adjustment method such as, for example, as disclosed in the Japanese examined patent publication Toku-Ko-Sho No. 52-41113, involves the superimposing of the optical axis of the visible laser beam on the axis of the infrared laser beam. Thereafter, the optical axis of the system as a whole is adjusted, using the visible laser beam. However, the superimposing operation of the optical axis is very difficult in presently existing technology, because a He-Ne gas laser, independent of the infrared laser, is used as the visible laser source. Furthermore, another problem is that detection of superimposed axes requires great skill.
The principal object of the invention is to provide laser apparatus having an easier adjustment of the optical axes of the invisible laser operating in the infrared or ultraviolet region than in known apparatus.
An object of the invention is to provide laser apparatus having an optical system providing a simplified optical axis adjustment for a semiconductor laser element which is used as an infrared laser source, particularly in a long-path gas monitor system.
Another object of the invention is to provide laser apparatus which can easily re-adjust the optical axes for replacement or repair of laser elements.